<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <p class="p"></p>
</body>
<script>
    function data(value) {
       document.getElementsByClassName("p") [0].innerHTML=value;
    }
</script>
<script src="http://localhost:1234/"></script>
</html>